They live in oceans throughout the world but are usually found in warm waters.
Sharks are remarkably successful animals. The first sharks lived on our planet more than 420 million years ago! They are fast and strong. They have very few parasites and are hardly ever ill. They have almost no enemies except other sharks.
Some people think that all sharks are big. But some kinds of sharks are no bigger than your hand. The smallest shark is about 16 centimeters long and weighs about 28 grams.
The biggest shark — and the largest of all fish — is the whale shark. It may grow up to 12 metres long and may weigh over 14 tons, over twice as much as an average African elephant! The whale shark has three thousand teeth but it will never bite you. It is quite harmless. It eats only tiny shrimp and fish.
Different sharks have different habits. Some kinds live in the depths of the ocean and are very seldom seen. Others are found near the surface. A few species enter rivers and lakes. Scientists believe that one species, the Ganges River shark of India and Pakistan, lives only in rivers.
Some sharks are loners, others like to gather together. Blue sharks are called the wolves of the sea because they stay together in packs.
Blue sharks often swim after a ship for days. A long time ago sailors thought this meant that someone was going to die. Today we know that sharks follow ships because of the noise they make. When the garbage is thrown into the water the sharks stop and eat it.
Most fish lay eggs. But most sharks do not. Their babies are born alive and completely developed. They do not need parental care. A baby shark is called a pup. The pup of the great white shark is almost the size of a man. As soon as they are born the pups go their own way. It isn’t safe to stay near a hungry mother.
A shark’s brain is small but its teeth are big. It has many rows of teeth. When a tooth breaks off a new tooth moves up to take its place. In some species new teeth replace the rows of older ones as often as once a week!
What do sharks eat with all these teeth? Fish and more fish, other sharks, seals, turtles, crabs. Almost anything that swims in the sea.
Sometimes sharks eat things that are not food. No one knows why. All these things have been found inside big sharks: a wallet, a drum, a bottle of wine, a chest of jewels and a suit of armour!
Do sharks eat people? Yes, they do. If a person is near a shark, the shark may attack. But it doesn’t happen very often. Fewer than 100 shark attacks a year are reported throughout the world.
The most dangerous shark in the sea is the great white shark. It is so named after its white belly. The great white shark may be more than 6 metres. It can sink a boat, it can bite a man in two, it can even swallow a man whole. It circles its prey, appearing from nowhere, and often approaching from below.
However, specialists say, more people die from bee stings than from shark bites!
Sharks do not go hunting for people. But people do go hunting for sharks. And then they have to be careful. A shark may look dead. Then all of a sudden it can ‘wake up’ — and attack!